In 20 17, the mortgage interest rates of postal services were 4.35%, 4.75% and 4.90%. According to relevant data, it is 4.35% within 6 months, 4.35% from June to 1 year, 4.75% from 1 to 3 years, 4.75% from 3 to 5 years and 4.90% from 5 to 30 years. On this basis, there will be appropriate downward floating or upward floating.